1. Field of the Invention
The present invention relates to a method and apparatus for encoding and decoding an audio signal such as a speech signal or a music signal, and more particularly, to a method and apparatus for encoding and decoding a high frequency signal by using a signal or a spectrum of a low frequency band.
2. Description of the Related Art
In general, signals of high frequency bands are regarded as less important sound to be recognized by humans in comparison with low frequency signal. Accordingly, when an audio signal is coded, if coding efficiency has to be improved due to a restriction of available bits, a signal of a low frequency band is coded by allocating a great number of bits, while a high frequency signal is coded by allocating a small number of bits.
Thus, when the high frequency signal is coded, a method and apparatus for maximizing the quality of sound to be recognized by humans by using the small number of bits are demanded.